The present invention relates to a novel polyamide composition excellent in impact strength which comprises a mixture of polyamide and a copolymer of ethylene series, the mixture having incorporated thereinto a coarbonate compound or a compound having an epoxy group or groups.
In general, polyamide is excellent in heat-resisting property, abrasion-and wear-resistance and electric characteristics. In particular, polyamide incorporated with an inorganic filler such as glass fibers or mineral powders is improved in heat-resistance, rigidity and mechanical properties. Thus, polyamide has been expected to find vairous uses as industrial resin utilizing these advantageous characteristic properties. Actually, however, the uses of polyamide are considerably limited because of its poor impact strength.
Proposed now to improve such poor inpact strength of polyamide is for example, blending 50-99% by weight of polyamide with 1-50% by weight of an olefin-unsaturated acid copolymer in which at least 10 percents of the unsaturated acid are neutralized with a metal ion (U.S. Pat. No. 3,845,163).
However, polyamide compositions obtained by the prior art methods wherein polyamide is reinforced with inorganic fillers to improve strength and rigidity of the polyamide had such a drawback that impact strength of the polyamide composition was seriously deteriorated instead. In addition, mere incorporation of a copolymer of thylene seires into polyamide was found disadvantageous in that the improving effect in modification of the properties was not significant. For the reasons referred to above, a polyamide composition fully satisfied from the viewpoint of improvement in impact strength has not yet been developed hitherto. Thus, there is still a great demand for developing a polyamide composition improved in various physical properties, in particular impact strength.
As a result of extensive researched made to overcome the drawbacks of the prior art polyamide compositions, the present invention has been accomplished.